Piezoelectric ceramic compositions

ABSTRACT

PIEZOELECTRIC CERAMIC COMPOSITIONS CONSISTING ESSENTIALLY OF A BASIC COMPOSITION INDICATED BY THE FORMULA:   XPB(SBNB)0.5O3-YPBTIO3-ZPBZRO3   WHERE:   X=0.5 TO 25.0 MOL PERCENT Y=36.0 TO 55.5 MOL PERCENT Z=53.5 TO 20.5 MOL PERCENT X+Y+Z=100 MOL PERCENT   AND FURTHER CONTAINING AT LEAST ONE METAL OXIDE SELECTED FROM THE GROUP CONSISTING OF THO2 AND CEO2 IN AN AMOUNT OF FROM 0.1 TO 3 PERCENT BY WEIGHT BASED UPON THE BASIC COMPOSITION.

Feb. 29, 1972 NQBQRU [cl-"NOSE EI'AL 3,645,974

PIEZOELECTRIC CERAMIC COMPOSITIONS Filed March 13, 1969 9 Sheets-Sheet 1 Fl 6. i

Pb(Sb Nb) 0 PbZrO PbT 1o 3o so Mason Mill/01E #013041 2/ YfiAO YA MA Min/ram! E 6AM! Y0 mm 2. 0 TA IVA/0,

INVEN'I'ORS git/ Feb. 29, 1972 NOBQRU 5 EI'AL 3,645,974

PIEZOELECTRIC CERAMIC COMPOSITIONS 9 Sheets-Sheet 2 Filed March 15,

SAMPLE 23 SAMPLE 51 w w 5 kzfimzoo 25855 TEMPERATURE SAMPLE 25 SAMPLE 31 TEMPERATURE c) -IOO Feb. 29, 1972 Filed March 13, 1969 DIELECTRIC CONSTANT NOBORU ICHINOSE ET AL 3,545,974

PIEZOELECTRIC CERAMIC COMPOSITIONS 9 Sheets-Sheet 4 SAMPLE 84 SAMPLE 96 TEMPERATURE (C) \SAMPLE 84 ELECTRO-MECHANICAL COUPLING COEFFICIENT 6 J SAMPLE 96 TEMPERATURE (C) Feb. 29, 1972 NOBORU [CHINOSE EI'AL 3,645,974

PIEZOELECTRIC CERAMIC COMPOSITIONS 9 SheetsSheet 5 Filed March 13, 1969 .PZEOFEMOQ O 75 PbTl'O3 PbZrO3 0 0Pb(SbNb)o. 0 3mm 05 5 3 1 PbZrO3 O 0 O O O 8 6 4 2 mm in flwshzyskmoo @2958 ll Feb. 29, 1972 NOBORU |CH|NQSE ETAL PIEZOELECTRIC CERAMIC COMPOSITIONS Filed March 15, 1969 9 Sheets-Sheet 6 0+- 12- 2 SAMPLEH? 8 E8 Q SAMPLE122 O u x -1o0 o 100 200 300 400 a TEMPERATURE (C) Fee. i 1 g5 70 Q g B: SAMPLE 122 E 355; 50 40- o SAMPLEH? E2 3O- 03? mil 20- d8 0- O 1O 1oo o 1 00 200 300 400 TEMPERATURE C) Feb. 29, 1972 Filed March 13, 1969 ELECTRO-MECHANICAL ELECTRO-MECHANICAL COUPLING COEFF|C|ENT(%) COUPLING COEFFICIENT(%) NOBORU ICHINOSE Er AL PIEZOELECTRIC CERAMIC COMPOSITIONS FIG! 9 Sheets-Sheet 7 I- z 80" I'-' 70- 2 LL. Kr 5&8 o 50 -2000 a B: 40 E: 30 3 QM I000 O 1 I0 0 I l O I5 45 6O 75 PbTIO3 79 64 49 54 I9 PbZrOa (mol 7O 5 6O Kr {5 -u- 50 2000 58 I 30 QM I I000 I; 20 I 3 I0 3 G O I I 0 0 I0 20 50 Pb(SbNb)0.5O 40 Pb Ti 05 e0 45 30 I5 p z (mol Feb. 29, 1972 NOBORU |H|NO$E ETAL 3,645,974

PIEZOELECTRIC CERAMIC COMPOSITIONS Filed March 13, 1969 9 Sheets-Sheet 8 g 70 SAMPLE 163 :E' 0 EE 50 8 SAMPLE 158 m B; -LJ

8 10" O l l l l i IOO O 100 200 300 400 TEMPERATURE 0) 14' 312 10- 3 SAMPLE 158 1 ,8 5 6 f 4 SAMPLE 163 O I 1 I l L IOO 0 I00 200 300 400 TEMPERATURE (C) United States Patent Oil-ice US. Cl. 252-623 1 Claim ABSTRACT OF THE DISCLOSURE Piezoelectric ceramic compositions consisting essentially of a basic composition indicated by the formula:

x: 0.5 to 25.0 mol percent y=36.0 to 55.5 mol percent z=53.5 to 20.5 mol percent x+y+z=100 mol percent and further containing at least one metal oxide selected from the group consisting of ThO and CeO in an amount of from 0.1 to 3 percent by weight based upon the basic composition.

The present invention relates to piezoelectric ceramic compositions, and more particularly to piezoelectric ceramic compositions mainly consisting of a basic composition formed of ternary oxides:

It is known that piezoelectric materials are employed in broad fields such as supersonic wave oscillation elements, ceramic filter elements, pickup microphones and oscillograph elements. Piezoelectric materials used in these applications are generally required to have a largest possible electro-mechanical coupling coeflicient Kr and mechanical quality coefficient Q For example, where a piezoelectric element is used as an electro-mechanical oscillation conversion element for a mechanical filter or an electro-sound oscillation conversion element associated with the oscillation of powerful supersonic waves, the greater the electro-mechanical coupling coefficient Kr, the higher the converting efliciency and in consequence the greater advantage for the formation of a circuit. Also, where a conversion is made among electro-mechanical sound oscillations, a large mechanical quality coefficient Q minimises loss in an oscillation element and loss of energies.

Piezoelectric materials heretofore known include, for example, a solid solution of the so-called Pb(ZrTi)O oxides consisting of substantially equal mols of PbTiO and PbZrO However, these piezoelectric materials have the drawbacks that they present considerable difliculties in sintering, and have a small mechanical quality coefficient Q and a relatively small electro-mechanical coupling coefficient Kr, so that they are not fully satisfactory for practical use.

The present invention has been accomplished in view of the aforementioned circumstances for providing piezoelectric oxide materials whose electro-mechanical coupling coefficient and mechanical quality coefiicient are sufiiciently large and which are prominently stable at ambient temperatures as well as during a long-term use and moreover can be easily manufactured on an industrial scale. To that end, in one aspect of the present invention, we provide piezoelectric ceramic compositions con- 3,645,974 Patented Feb. 29, 1972 sisting essentially of a basic composition indicated by the formula:

x=0.5 to 25.0 mol percent y=36.0 to 55.55 mol percent z=53.5 to 20.5 mol percent x+y+z= mol percent In other aspects of the invention, the ceramic compotions also include appropriate amounts of a metal oxide selected from the group of ThO CeO ThO mixed with (3e0 MnO Cr O NiO, C00 and NiO mixed with C00.

The present invention can be more fully understood from the following detailed description when taken in connection with the accompanying drawing.

FIG. 1 is a triangular compositional diagram showing the relative proportions of constituting a basic composition of piezoelectric oxide materials according to the present invention;

FIG. 2 is a curve diagram representing the relationship between the dielectric constant of piezoelectric materials prepared according to an embodiment of the invention and ambient temperatures;

FIG. 3 is a curve diagram indicating the relationship between the piezoelectric properties of said materials and ambient temperatures;

FIG. 4 is a curve diagram showing the relationship of the varied proportions of PbTiO and PbZrO to the piezoelectric properties of the present product as a whole where the proportions of ThO and/or CeO each forming an auxiliary composition thereof and Pb(SbNb) O a component of the basic composition thereof, are fixed;

FIG. 5 is a curve diagram denoting the relationship of the varied proportions of to the piezoelectric properties of the present product as a whole where the proportions of said ThO and/or CeO are fixed;

FIG. 6 is a curve diagram illustrating the relationship between the dielectric constant of piezoelectric materials prepared according to another embodiment of the invention and ambient temperatures;

FIG. 7 is a curve diagram of the relationship between the piezoelectric properties of said materials and ambient temperatures;

FIG. 8 is a curve diagram showing the relationship of the varied proportions of PbTiO and PbZrO to the piezoelectric properties of the present product as a whole where the proportions of NiO and/or C00 each forming an auxiliary composition thereof and Pb(SbNb) O a component of the basic composition thereof, are fixed;

FIG. 9 is a curve diagram representing the relationship of the varied proportions of Pb(SbNb) O PbTiO PbZrO to the piezoelectric properties of the present product as a Whole where the proportions of said NiO and/ or CoO are fixed;

FIG. 10 is a curve diagram indicating the relationship of the dielectric constant of piezoelectric materials prepared according to another embodiment of the present invention to ambient temperatures;

FIG. 11 is a curve diagram denoting the relationship of the piezoelectric properties of said materials to ambient temperatures;

FIG. 12 is a curve diagram representing the relationship between the varied proportions of PbTiO and PbZrO and the piezoelectric properties of the present 3 piezoelectric product as a whole where the proportions of Cr one of the auxiliary compositions thereof, and Pb(SbNb) O a component of the basic composition thereof, are fixed;

FIG. 13 is a curve diagram illustrating the relationship between the varied proportions of tPb(SbNb) O PbTiO -PbZr0 and the piezoelectric properties of the present product as a whole where the proportions of said Cr O are fixed;

FIG. 14 is a curve diagram showing the relationship of the dielectric constant of piezoelectric materials prepared by another embodiment of the present invention to ambient temperatures;

FIG. 15 is a curve diagram denoting the relationship of the piezoelectric properties of said materials to ambient temperatures;

FIG. 16 is a curve diagram indicating the relationship of the varied proportions of PbTiO and PbZrO, to the piezoelectric properties of the present product as a whole Where the proportions of MnO one of the auxiliary compositions thereof, and Pb(SbNb) -O a component of the basic composition thereof, are fixed; and

FIG. 17 is a curve diagram showing the relationship between the varied proportions of Pb(SbNb) O PbTiO PbZrO and the piezoelectric properties of the present product as a whole where the proportions of said MnO are fixed.

As mentioned above, the proportions of Pb(SbNb) 0 a component of the basic composition of piezoelectric oxide materials according to the present invention consisting of Pb(SbNb) O PbTiO PbZrO are suitably selected within the range of 0.5 to 25.0 mol percent on the basis of said basic composition. It the proportions of said Pb(SbNb) O exceed 25.0 mol percent the electromechanical coupling coeflicient Kr of the piezoelectric product as a whole will fall below the level of about 40% which is required when the product is put to practical applications such as pickup elements, or microphones. And it said proportions decrease from 0.5 mol percent, there will be presented difiiculties in the sintering operation to produce compact and mechanically strong piezoelectric materials. Moreover, the resultant product will have too low an electro-mechanical coupling coefficient Kr for satisfactory industrial application.

The proportions of PbTiO- another component of said basic composition, are suitably selected, as described above, within the range of 36.0 to 55.5 mol percent on the basis of said basic composition. If the content of said PbTiO falls outside of this range, it will be impossible to obtain a piezoelectric product whose electro-rnechanical coupling coefiicient Kr is suffiicently large and less affected by amibent temperatures and long-term use, and in consequence adapted for industrial application as a supersonic wave oscillator.

The proportions of PbZrO another component of the aforementioned basic composition, are suitably selected within the range of 3.5 to 20.5 mol percent on the basis of said composition. If the percentage of said PbZrO departs from this range the resultant piezoelectric product will not'have a large electro-rnechanical coupling coeflicient Kr and in consequence be reduced in practical value.

For the foregoing reason, the three components Pb(SbNb) O PbTiO and PbZrO of the basic composition of piezoelectric materials according to the present invention are used in a ratio suitably selected from the range shown in the triangular compositional diagram of FIG. 1.

Further T1102, C302, Nioz, COO, C1' O and MHO added as an auxiliary composition to the aforementioned basic composition act as a sort of mineraliser to facilitate sintering, reduce temperatures required therefor, and suppress the evaporation of PbO constituting part of the basic composition, thereby enabling compact piezoelectric matei'ials to be finally obtained. The added proportions of the auxiliary compositions having such function are separately determined for the reason given below.

ThO CeO or mixtures thereof are preferably added within the range of 0.1 to 3 percent by weight on the basis of the basic composition. If their proportions exceed 3 percent by weight the resultant piezoelectric product will be conversely reduced in the mechanical quality coefficient Q This will lead to decrease in its specific resistance, as a result the occurrence of conduction and shorting while a DC. voltage is being impressed, and imperfect polarisation, making it impossible to improve said mechanical quality coefficient Q If, on the contrary, addition of these auxiliary compositions falls below 0.1 percent by weight, the resultant product will not be much elevated in the mechanical quality coetficient Q failing to display the desired excellent piezoelectric properties.

In the case of NiO, CoO or mixture thereof, their addition is preferred to fall within the range of 0.1 to 2.5 percent by weight on the basis of the basiccomposition. Beyond 2.5 percent by weight, these auixilary compositions will cause the resultant piezoelectric product to decrease in the mechanical quality coefiicient Q and conversely below 0.1 percent by weight, will not enable the product to be much improved in this respect and exhibit the desired prominent piezoelectric properties. i

It is preferred that Cr 'O or MnO be used within the range of 0.01 to 2 percent by weight on the basis of the basic composition. Their addition in excess of 2 percent by weight will reduce the mechanical quality coefi'lcicnt Q of the resultant piezoelectric product and their proportions of less than 0.01% will not enable the product to have a much improved mechanical quality coeflicient Q and as a result display the desired high piezoelectric properties.

Piezoelectric oxide materials of the present invention consisting of the aforementioned compositions are prepared by solid solution reaction from a plurality of oxides having different valences. They can be easily fabricated by general powder metallurgical techniques or other 'known methods. To describe by way of illustration, the prescribed proportions of raw oxide materials, for example, PbO, TiO Zr'O Sb O Nb O and auxilary compositions such as ThO are exactly weighed out and mixed in a ball mill or the like. The raw materials used in the present invention may of course include other compounds such as hydroxides, carbonates or oxalates which will be converted to oxides by addition of oxygen.

The aforesaid mixture is presintered at relatively low temperatures such as 600 to 900 C., and crushed into mixed powders using a ball mill or the like. Then to these mixed powders is added a binding agent such as water or polyvinyl alcohol. The mass is moulded at a pressure of about 0.5 to 2 ton/cm. and finally sintered at temperatures of about 1160 to 1280 C. Since part of the PbO is liable to be evaporated and dissipated during this sintering operation, it should preferably be carried out Within a sealed furnace. If the mass is maintained 0.5 to 3 hours at predetermined maximum temperature, it will fully serve the purpose. The piezoelectric oxide materials thus prepared can be polarised by disposing on both sides thereof a known means, for example, a pair of electrodes and impressing a DC. voltage of 20 to 30 kv./cm. for an hour at temperatures of to C.

The piezoelectric oxide material obtained assumes the form of a solid solution in which there are uniformly dispersed PbO, TiO ZrO Sb O and Nb O The X-ray difiractometry disclosed that the mass had a perovskite structure. Expressed by the general formula ABO the piezoelectric oxide material consists of a combination of elements having diiferent valences, such as divalent Pb represented by A, and trivalent Sb, pentavalent Nb, tetravalent Ti and Zr denoted by B. Accordingly, the piezoelectric oxide material of the present invention is essentially different from the prior art piezoelectric material which mainly consists of an octahedral oxygen atom, namely, has such a composition which, expressed by the general formula A'BO comprises three types of element Piezoelectric propertles e Kr QB maximum temperature of 1210 to 1280? C. in a sealed furnace, obtaining a disk 13 mm. in diameter and 1 mm. thick- Each sintered body was measured for its density D at23 C., and polarised in a silicon oil at a temperature of 140 .C. by fitting a pair of electrodes to both sides thereof and impressing 1 hour in DC voltage of kv./cm. across them. The piezoelectric properties of the sintered body were measured using a standard circuit described in Proceeding of IRE, vol. 137 (1949), pages (1958), pages 765-778, and also the dielectric constant of said sintered body was determined by customary means. The results of these determinations are presented in Table I below.

TABLE I Main composition (mol percent) Auxiliary composition Pb(SbNb)0.5O; PbTiO; PbZrOa (wt. percent) F.T.

combination, i.e, (i) where A represents a divalent elevalent element and B a tetravalentelement, (ii) where A denotes a monovalent element and B' a pentavalent element, and (iii) where both Af'and Bf express equivalent elements.

As mentioned above, the piezoelectric oxide materials according to the present invention not only have a fundamentally different composition from that of the conventional binary or ternary piezoelectric materials such as PbTiO PbZrO or PbTiO PbZrO PbSnO but also a 10 1378-1395, vol. 145 (1957), pages 353-358 and vol. 146 large electro-mechanical coupling coefiicient Kr and an excellent mechanical quality coefiicient Q Accordingly, the product of the present invention is prominently adapted for use in pickup elements, microphones, oscillo- Sample No.

7 7 7 7 7 7 7 7 7 7 Z-L. -LTZTl- TZ- -LTTTI TTZ- TT- TF IZ 1 12 1 Manama new manna Manna TTCC TTTCCCTC TTTCCC TTTCCC TTTCCC TTTCCC .0 000000000000000000000000000000005555555 %66&6 0 0 0 0 0 O 0 O 4 id iATe tQQQQQQQdfifiQfibGOQO0000 2222 222111 11111 Throughout Table I above and Tables II, III and IV associated with other examples, F.T. represents a sintering temperature C.), d. a density (g./cm. at 23 C.), e a dielectric constant (1 kc./sec. at 23 C.), KI an electro-mechanical coupling coefiicient (percent) and Q a dth of mechanical quality coeflicient.

the invention or limit the scope of the patent claims When investigation was made of changes with time in appended hereto the dielectric constant of samples Nos. 23 and 31 in Table I above, there were obtained the results shown in FIG. 2. The Curie points of both samples presented values as high as 320 and 350 C. The temperature characteristics of the electro-mechanical coupling coefficient Kr of these piezo-electric samples were also determined and the results are presented in FIG. 3. The high Curie points of d 65 said sampllles reduced the range of changes with temperature in t eir e ectro-mechanical coupling coeflicient Kr therein varied to 26, 20, 14, 10, 6 and 0.5 mol percent over a temperature range of to 200 C. p g that a fully high elcctro-mechanical coupling coefiicient Kr could be utilised under a stable condition.

EXAMPLE 2 There were prepared various combination of raw materials with addition of Th0; fixed at 1.0 percent by weight, the proportions of Pb(SbNb) O also fixed at strial application.

learly appreciated ll be understood, are ofiered only by way of illustration d ThO ng an auxiliary composiwith the proportions of PbTiO included in said basic composition fixed at 48 graphs, or transducers and can be easily manufactured, ofiering very great advantages in indu The present invention will be more c from the examples which follow. It wi however, that they and are not intended to restrict the scope or brea EXAMPLE 1 The prescribed proportions of PbO, TiO ZrO Sb O and NbO constituting a basic composition, an Ce0 or mixtures thereof formi tion were exactly weighed out,

mol percent, the proportions of Pb(SbNb) O include and the proportions of PbZrO similarly included therein varied to 26, 32, 38, 42, 48 and 51.5 mol percent. After being fully mixed in a ball mill, these materials were presintered 1 hour at a temperature of 850 C. and crushed again in a ball mill, obtaining a large number of samples of mixed powders as listed in Table I given later. To each sample was added a binding agent of polyvinyl alcohol, and the mass was moulded at a pressure of 1 ton/cm. and then finally sintered 1 hour at a 8.0 mol percent, and the proportions of PbTiO and PbZrO varied in turn. All these mixtures were processed in substantially the same manner as in Example 1, ob.- taining many kinds of piezoelectric samples. Determination' was made of the relationship of 'piezoelectric properties versus composition of each sample, the results being presented in FIG. 4.

ample Lfobtaining a sintered disk, 13 mm. in diameter and 1mm. thick. The sintered body was measuredfbr its density (d) and polarised in the same manner as in Example 1. Determination was also made of the pieio electric properties and dielectric constant offthe' sintered body, the results being presented in Table II below.

TABLE II Piezoelectric prop Main composition (moi percent) Auxiliary erties Sample composition No. Pb(SbNb) O PbTiOa PbZr (wt. percent) F11. d. e Kr Q 25. 0 48. 0 26. 0 0 1, 280 7. 23 2, 880 38. 4 195 25. 0 48.0 26. 0 C00 0.4 1, 270 7.34 2, 655 39. 2 240 26. 0 48.0 26. 0 C00 1.5 1, 260 7. 40 2, 590 39. 290 20.0 48. 32.0 0 1, 280 7. 26 2, 700 40.3 175 20.0 48. 0 32.0 000 0 2 1, 270 7. 38 2, 680 41. 5 280 20. 0 48.0 32.0 C00 1.0 1, 260 7. 41 2,650 42. 4 435 20.0 48.0 32. 0 000 1.5 1, 250 7. 44 2, 585 41. 8 370 20.0 48.0 32. 0 000 2.0 1, 250 7. 39 2, 575 41. 3 280 20.0 48.0 32. 0 000 2.5 1,250 7. 37 2, 540 40.8 205 20. 0 48.0 32. 0 NiO 0.2 1, 270 7. 2, 660 40. 8 295 20.0 48.0 32.0 NiO 1.0 1, 260 7. 2, 645 42.2 405 20. 0 48. 0 32. 0 N10 1.5 1, 250 7. 45 2, 595 41. 7 325 2D. 0 48. 0 32. 0 NiO 2.0 1, 250 7. 43 2, 560 41. 1 290 20.0 48. 0 32.0 NiO 2.5 1, 250 7. 41 2, 570 40.8 190 20. 0 48. 0 32.0 N10 3.0 1, 250 7. 35 2, 525 40.0 150 14. 0 48.0 38. 0 0 1, 280 7. 28 1, 950 42. 8 150 14. 0 48. 0 38. 0 C00 0.3 1, 270 7. 38 1, 970 44. 6 365 14.0 48. 0 38. 0 C00 1.0 1,250 7. 2, 000 44. 9 400 14. 0 48.0 38.0 G00 1.5 1, 240 7. 46 1, 945 43. 8 310 14.0 48.0 38.0 000 2.0 1, 240 7. 44 1, 920 42.9 285 14. 0 48. 0 38.0 NiO 0.3 1, 270 7. 39 1, 985 43. 7 270 14.0 48.0 38.0 NiO 1.0 1, 250 7.51 2,005 45. 1 455 14. O 48.0 38. 0 NiO 1.5 1, 240 7. 50 1, 970 44. 4 350 14.0 48.0 38.0 NiO 2.0 1, 240 7. 43 1, 945 43. 0 215 10.0 48. 0 42.0 0 l, 280 7. 46 1, 275 46. 8 135 10. O 48.0 42. 0 000 0.5 1, 260 7. 54 1, 390 48.1 320 10.0 48.0 42. 0 000 1.0 1, 240 7. 56 1, 385 49. 2 660 10.0 48. 0 42.0 000 2.0 1, 230 7.50 1, 360 47. 7 300 10. 0 48. 0 42. 0 N10 0.5 1, 260 7. 53 1, 345 47. 5 290 10.0 48.0 42.0 N10 1.0 1, 240 7. 58 1,370 48.8 740 10. 0 48. 0 42.0 NiO 2.0 1, 230 7. 51 1,305 47.0 295 5. 0 48.0 47. 0 0 1, 270 7. 38 1, 180 51. 6 260 5.0 48.0 47. 0 000 0.5. 1, 260 7. 60 1, 200 57.6 350 5.0 48.0 47.0 C00 1.0 1,240 7.65 1, 240 59. 1 955 5.0 48.0 47. 0 C00 1.5 1, 230 7. 61 1, 225 58. 0 1, 050 5. 0 48. 0 47. 0 C00 20 1, 210 7. 56 1, 210 54. 4 495 5. 0 48. 0 47. 0 NiO 0.5 1, 250 7. 63 1, 205 53. 3 410 5.0 48. 0 47. 0 NiO 1.0 1, 240 7. 1, 290 51. 4 870 5. O 48.0 47.0 NiO 1.5 1, 230 7. 66 1, 260 58.8 915 5.0 48.0 47.0 N10 2.0 1,220 7.53 1,250 54.6 395 0. 5 48.0 51. 5 0 1, 270 7.37 1,040 42. 6 205 0. 5 48. 0 51.5 C00 0.5 1, 260 7.45 1, 44.1 270 0. 5 48.0 51.5 000 1.0. 1, 240 7. 55 1,180 45.2 630 0. 5 48. 0 51.5 C00 2.0 1,230 7. 53 1,145 44. 0 410 0. 5 48.0 51. 5 N10 0.5 1, 260 7.47 1,110 44. 8 290 07 5 48. 0 51.5 NiO 1.0 1, 240 7.59 1, 195 46. 0 710 0. 5 48.0 51. 5 NiO 2.0 1, 230 7. 50 1, 45. 3 455 0. 5 48.0 51. 5 Ni() 3.0 1, 230 7. 52 1, 130 41. 8

EXAMPLE 3 There were prepared various combinations of raw materials with addition of CeO fixed at 1.3 percent by weight and the proportions of Pb(SbNb) O PbTiO and PbZrO varied. All these mixtures were processed in substantially the same manner as in Example 1 to prepare many kinds of piezoelectric samples. Determination was made of the relationship of piezoelectric properties versus composition of each sample, the results being indicated in FIG. 5.

EXAMPLE ,4

There were weighed out the prescribed proportions of PhD, T102, ZIOZ, Sb03, $13203, Nb205, and COO with the proportions of PbTiO a component of the basic composition, fixed at 48 mol percent, the proportions of Pb(SbNb) O involved in said basic composition varied to 26, 20, 14, 10, 5 and 0.5 mol percent and the proportions of PbZrO another component of said basic composition, varied to 26, 32, 38, 42, 47 and 51.5 mol percent, and the proportions of 'NiO, C00 or mixtures thereof set at 0 to 3 percent by weight on the basis of said basic composition. After being fully mixed in a ball mill, these materials were presintered at a temperature of 850 C. They were again crushed in a ball mill, obtaining a large number of samples of mixed powders as listed in Table I. To each sample was added polyvinyl alcohol and the mass was processed in the same manner as in Ex- When determination was made of changes with temperature in the dielectric constant of samples Nos. 84 and 96 in Table II above, there were observed the tendencies shown in FIG. -6. The sample displayedhigh Curie points as 320 and 360- C. I I

The temperature characteristics of the electro-mechanical coupling coefiicient Kr of said samples were also determined obtaining the results shown in FIG. 7. Their high Curie points reduced the range of changes with time in the electro-mechanical coupling coefiicient Kr over a temperature range of -60 to 200 C., proving that a fully high electro-mechanical coupling coeflicient Kr could be utilised under a stable condition.

EXAMPLE 5 There were prepared various combinations of raw materials, with addition of ThO fixed at 1.1 percent by weight,

' the proportions of Pb(SbNb) O also fixed at 6.0 mol percent and the proportions of PbTiO and PbZrO varied in turn. Each sample was processed in substantially the same way as in Example 1 to obtain a piezoelectric material. The relationship of piezoelectric propertiesversus composition of the sample was determined, the results being presented in 'FIG. 8. V 7

EXAMPLE 6 There were prepared various combinations of raw materials with addition of C00 fixed to 0.8 percent by weight 9 10 on the basis of the basic composition and the propor- EXAMPLE 8 tions of Pb(SbNb) 0 PbTiO and PbZrO varied. Each Th Z ere werere ared various combmations of raw mat was processed m substailtlany Same .manner terials with ad dit ibn of Cr O;, fixed at 0.5 percent by as P 1 to prepare a plez.oelec.mc a Weight, the proportions of Pb(SnNb) O also fixed at termination was made of the relationship of piezoelectric 5 6 0 m 01 percent and the proportions" of PbTiO and propert es versus composition of the sample, the results PbZrO3 varied in turn obtaining a large numbaer of bemg given m samples of mixed powders. Each sample was processed EXAMPLE 7 in substantially the same manner as in Example 1 to form There were exactly weighed out the prescribed propop 10 a piezoelectric material. Determination was made of the tions of Pbo Z102 sbzos and Nbzos constituting the relationship of piezoelectric properties versus composibasic composition and crzos as an auxiliary composition non of the sample, the results belng given 1n FIG. 12.

with the proportions of PbTiO a component of the basic EXAMPLE 9 There were prepared various compositions of raw materials with addition of Cr O fixed at 0.5 percent by weight on the basis of the basic composition,

composition, fixed at 49 mol percent, the proportions of Pb(SbNb) O varied to 26, 20, 14, 10, 4 and 0.5 mol percent, the proportions of PbZrO varied to 26, 32, 38,

42, 48 and 51.5 mol percent, and the proportions of Cr O and the as an auxiliary composition varied to 0 to 2 percent by PTOPOTUOHS of 0.5 3 T s and PbZrOa weight Aft being fully mixed in a ball mill, these varied. Each sample was processed msubstantially the terials were presintered 1 hour at a temperature of 850 C. manner as f p 1 to P p a plgloelqctfic m They were again crushed in a ball mill, obtaining a large D was made of i relatlonshlp 0f P number f Samples f mixed powders listed in Table 1 electric properties versus composition of the sample, the

results being given in FIG. 13.

given later. To each sample Was added polyvinyl alcohol and the mass was processed in the same way as in Example 1, obtaining a sintered disk 13 mm. in diameter and 5 EXAMPLE 10 1 mm. thick. The sample was determined for its density There were exactly weighed out the prescribed propor- (d.) and polarised in the same manner as in Example 1. tions of PbO, TiO ZrO Sb O NbgO constituting the Determination was made of the piezoelectric properties basic composition and MnO as an auxiliary composi and dielectric constant of the sample, the results being tion, with the proportions of PbTiO a component of the given in Table III below. basic composition, fixed at 48 mol percent, the propor- TABLE III Piezoelectric Sample No.

05550505005050fi5000500 68 6 3856754 91 83100 N6MW54999888 343331 04 10205000 30500150500 0 L O LL2Qw 0 L12 001 212 66 0 4444440000 04 22%m2%m%%1111111111m1 tions of Pb('SbNb) O another component of the basic When determination was made of changes with temperature in the dielectric constant of samples Nos. 117 and composition, varied to 26, 20, 15, 10, 5 and 0.5 mol per- 122, there were observed the tendencies shown in FIG. 65 cent, the proportions of PbZrO also another composition 10. The samples had as high Curie points as 315 and 345 of the basic composition, varied to 26, 32, 37, 42, 47 and C. The temperature characteristics of the electro-mechani- 51.5 mol percent, and the proportions of MnO as an cal coupling coefiicient Kr of the samples were deterauxiliary composition varied to 0 to 3 percent by weight. mined, obtaining the results given in FIG. 11. Also in After being fully mixed in a ball mill, these materials were this case, their high Curie points reduced the range of presintered at a temperature of 600 to 900 C. They were changes with temperature in their electro-mechanical again crushed in a ball mill, obtaining a large number of coupling coeflicient Kr over a temperature range of 60 samples of mixed powders listed in Table IV given later. to 200 C., proving that a fully high electro-mechanical To each sample was added polyvinyl alcohol and the mass coupling coefiicient Kr could be utilised under a stable was processed in the same manner as in Example 1, obcondition. taining a sintered disk 13 mm. in diameter and 1 mm.

Each sample was processed in substantially the'j'sam'e way as in Example 1 to prepare a piezoelectric rnate'rial, Def termination was made of the relationship of piezoelectric properties versus composition of theisample, the results 1. A piezoelectric ceramic material consisting essential 1y of a basic composition indicated by the formula? xPb (Sb'Nb O yPbTiO -zPbZrO and at least one metal oxide selected from the group consisting of T110 and Ce in an amount of from 0.1 to 3 percent by weight based upon the basic composition.

1 t f. n D H m Z? 7 0050000050005550000055.3000050005 r f C 0.04 994 886157603 46901 11 19 f m. 22312saziiavasziaavszimmmnnztensi w m m a G w 1 2 1 11 P 0 1 1 hr O O O H ee .m m m o H mm 505681628206538718618237376569896 m m e m GWQW .L LLOwowAm 2 Lanny 05 $306 5 023 Lu w 55 1 HP 33 44Q44344%4M444444M5655 544%443 o n 552 1 T C 53 7.01 1 01 5 l 50 O m. e .m&%w%%s%384%.%W5Mm42%O%H%7mwum%Bw5fl 8 O t w m 2222222 2221l1l1 11111111l1 11 IT t P a 0 3 5 y 8015 9068 16 152 39 80 9 1 S2 6 d %3433%Q3444= u55 555%65fifi56fifi4fl5fl44 h T T 7 7 777 7 7 7 7 7 7 77 7 7 7 7 717111711117117? W m x V. Z x 6 b W 000 0 000000 00000000000000 00000 66 6 542665 fi -664331 3211 65321 5 22 2222222222 2222222%%2222222222 F 1 1 11ILLLLlllLLLlLlLlLLLllll lLLLll 0500205000 30500150500m5050025000 0L 0 1 2513 .0 LL2 0 0LL2 QLLZ 0 0 L2nw Addition of M1102. wt; percent Ifk ..df .w m mnm m wm meta. a mmww i m mm w n m 5 n w f a d ms 1 ni w w d w S n. r .6 6 e mwuw n mmmmmwmm ma a H S n h .n r E p .1 S .m m n v. L. mus 000000O00000000000000000000555555 mafi up d v r m m m i dam m H m nnnawnm wmammmwnnnanng mnnnn w mommwmm c 6 a T m b mS f d &6 H.116 e P C [C d S m mm m m ew ammmm r m 1 1 t M. 000000000000000000000000000000000 mm m h l t k w mum m %%%QQQQQQQQfiuafififiwfiawfifllawflfimfiwfiwfi m W n aQ Mmm t WM snn m m rtP m m mes fi 0P f e f afi s. n s Ohki r 1 w s rm m n a o m c c m m e a u ..V..6 p N w 000000000000000000000000000555555 W C T. 3 emmc U V t w m ssandmannoasaaaaoauuonwaanaaaouuunu f dmc toa mma 0 22222 222111111111 11 nn n nnw P 0 a e ama mm fima fi m m edfid m. n. I nin a 6 M .m m vk 6SC8 b OC mnh mm P m n w m. m mm mmmwe mmn se e e r I e b h o .,o e n. e.. m m a m m C mwm m m 3. m i m ma ma m mm smaan fimw 166 1 eu e an H mm mm. s n piacmmmmwww References Cited UNITED STATES PATENTS 3,544,471 12/1970 Tsubouchi et 'al. 252-62.? 3,268,453 8/1966 Ouchi et a1. 25262.9 3,376,226 4/1968 Akashi et al. 252-629 3,403,103 9/1968 Ouchi et a1. 25262. 9 3,484,377 12/1969 Tsubouchi et a1. 25262.9 3,487,019 12/1969 Tsubouchi et a1. 252-629 JAMES E. POER, Primary Examiner J. COOPER, Assistant Examiner U.S. 'Cl.'X.R.

condition.

EXAMPLE 11 There were prepared various combinations of raw materials, with addition of MnO fixed to 0.5 percent by Weight on the basis of the basic composition, the proportions of Pb(SbNb) O also fixed at 7.0 mol percent and the proportions of PbTiO and PbZrO varied in turn. Each sample was processed in substantially the same manner as in Example 1 to prepare a piezoelectric material. Determination was made of the relationship of piezoelectric properties versus composition of the sample, the results being given in FIG. 16.

EXAMPLE 12 There were prepared various combinations of raw materials, with addition of MnO fixed to 0.5 percent by weight on the basis of the basic composition and the pro- 5 106 39 R portions of Pb(Sb'Nb) O PbTiO and PbZr0 varied. 

